Bucket ladder dredger

ABSTRACT

A bucket dredger comprises a pontoon and a bucket ladder mounted on the pontoon for bodily vertical swinging movement relative to the pontoon. The ladder mount comprises vertically swinging arms pivotally interconnected to the pontoon and to the ladder and jacks for swinging the arms. The ladder carries rollers that roll on an upwardly inclined track on the pontoon, the summit of the track being intermediate its ends so that in an upwardly swung position the ladder will be horizontal. The support arms extend beyond the point of pivotal connection to the ladder and at their free ends are connected by links to a chute which is thus maintained vertical in all positions of the ladder.

United States Patent van der Gaag 51 Aug. 1, 1972 [54] BUCKET LADDER DREDGER FOREIGN PATENTS OR APPLICATIONS [72] Inventor: Cornelis van der Gang, Delft, 220,089 3/1962 Austria ..37/69 Netherlands 267,707 5/ 1964 Netherlands ..37/69 694,589 9 1964 d ..37 9 731 Assignee: N.V. Industrieele Handelscombinatie a /6 Holland, Rotterdam, Netherlands primary Examiner Roben p n- 22 Filed; May 13 1970 Assistant Examiner-Clifford D. Crowder Attorney-Young & Thompson [21] Appl. No.: 36,983

[57] ABSTRACT [30] Foreign Application Priority Data A bucket dredger comprises a pontoon and a bucket ladder mounted on the pontoon for bodily, vertical May 13, 1969 Netherlands ..07346/69 swinging movement relative to the pontoon The ladder mount comprises vertically swinging arms [52] U.S.Cl. ..37/69,37/86, 37/191 R pivotany interconnected to the pontoon and to the Int. Cl. ladder and jacks for swinging the arms The ladder Field Search 191 carries rollers that roll on an upwardly inclined track on the pontoon, the summit of the track being inter- [56] References Cited mediate its ends so that in an upwardly swung position the ladder will be horizontal. The support arms extend UNITED STATES PATENTS beyond the point of pivotal connection to the ladder and at their free ends are connected by links to a 2,750,687 6/1956 Banister ..37/90 chute which is thus maintained vertical in all positions 640,762 1/1900 Gray ..37/69X ofthe ladder 2,636,288 4/1953 Thomas ..37/69 X g 2,747,307 5/1956 Griffin ..37/90 5 Claims, 1 Drawing Figure l I I v i I '7 1 Nfl i "Illx r12: t 4

PATENTEDAUB 1 I972 INVENTOR Cam 1 /.9 WM 015/? 6446 BY M v ATTORNEYS BUCKET LADDER DREDGER The invention relates to a bucket ladder dredger which comprises a pontoon and a bucket ladder which, pivoting about a horizontal cross axle near its upper portion, is mounted to a derrick mounted on the pontoon, while it is furthermore provided with means for lowering and raising the lower portion of the bucket ladder. Such a dredger is generally known. With such dredgers the upper portion of the ladder is pivotally connected to a main derrick rigidly mounted on the pontoon, while the lower portion of the bucket ladder is suspended from a ladder derrick with chains, while the lower portion of said bucket ladder may be vertically adjusted by means of said chains. With these dredgers the main derrick generally supports the drive of the upper wheel of the bucket chain.

The presence of a main derrick and a ladder derrick makes this known dredger expensive to construct. In addition to this said derricks require the center of gravity of the entire machine to be in a substantially elevated position, which does not make for a greater stability of the dredger. Furthermore lowering the ladder becomes a most difficult procedure, if it is possible at all, while when dredging in shallow waters the lower portion of the bucket ladder will extend beyond the pontoon to a greater extent than when dredging in deep waters, consequently the center of gravity will be displaced to a more or less forward position depending on the depth adjustment of the bucket ladder. This has an influence on the longitudinal trim of the pontoon, while the vertical forces acting on the ladder influence the pontoon to a greater extent in this more forward position. If the lower wheel has to be overhauled, repairs cannot be made from the pontoon, since the bucket ladder extends far beyond the pontoon in an upright position.

It is the object of the invention to provide a dredger by which these difficulties are overcome and this object is achieved according to the invention by the fact that the derrick comprises a support means pivoting about a horizontal cross axle and connected to the pontoon, means for adjusting the ladder, which means comprise an adjusting device which engages the support means and with which the upper portion of the ladder may be swung in the longitudinal direction of the pontoon, as well as a guide track sloping in a vertical direction from the pontoon for the guide rollers to said ladder, which guide rollers are positioned between the ends of the bucket ladder. Said adjusting means may be designed in any suitable way, though they will generally consist of hydraulic cylinders which will engage the support means from another point of the pontoon. This support means preferably consists of a portal which is transversely mounted on the pontoon, the legs of which portal are pivotally mounted on the pontoon, while the upper portion of said portal is pivotally mounted to the upper portion of the ladder. If with the aid of the adjusting means the support means is swung outwards from the lowest position, the upper portion of the ladder will travel in the longitudinal direction of the pontoon, while that portion of the ladder which rests on the rollers will travel upwards along the guide track together with said rollers. By a proper choice of the dimensions and slope of the guide track, the front or lower portion of the bucket ladder may be urged to travel in a substantially vertical direction, so that the center of gravity of the entire dredger will hardly be displaced at all. The structure is much simpler than the known structure, inasmuch as there are only to be provided one portal, two adjusting cylinders and two guide tracks of a relatively low height.

Furthermore according to the invention the guide track, beyond the upper portion thereof, may slope in a downward direction to end with a portion that is at such a height above the pontoon that the ladder, in the outermost position of the adjusting means, will take up a substantially horizontal position. Thus by moving the adjusting means beyond the topmost position of the ladder, the ladder will move over the top of the guide track together with the rollers and will subsequently move down again whereby a position will be attained in which the ladder will take up a horizontal position at a relatively low height above the pontoon, so that the lower part may be supported by the pontoon. There is thus obtained a lowered position of the ladder, which enables the dredger to pass under certain bridges, while the carrying out of repairs to the bucket ladder is simplified.

The upper portion of the bucket ladder of a dredger is generally provided with a discharge chute for the conveyance of the dredged material which has fallen out of the buckets to a further storage or conveying means. According to the present invention the discharge chute may be pivotally mounted on the ladder and held in a vertical position by means of a parallel guide bar which is pivotally connected to the support means, which vertical position is maintained in any position taken up by the ladder.

The invention will now be further elucidated with reference to the drawing which shows a diagrammatic view in side elevation of a dredger according to the invention.

The drawing shows a pontoon l with a bucket ladder 2. Said bucket ladder is supported on a guide track 4, which extends in an upward direction, by rollers 3, while it is furthermore supported through the support means 5 designed as a portal. The support means 5 is pivotally connected on the pontoon at 6 and pivotally mounted to the bucket ladder at 10. On the pontoon is pivotally mounted a hydraulic cylinder 9 at 8, which cylinder engages the portal 5 at 10. A discharge chute 12 is pivotally connected to the upper portion of the ladder at 11 and is furthermore connected at 7 to the upper portion of the portal 5 by the bar 13. The topmost position of the ladder is shown in the drawing with interrupted lines, and this position shows that the bar 13 is mounted and dimensioned in such a way that the chute is maintained in a vertical position.

The guide track 4, beyond the uppermost portion thereof, is shown as having a downwardly sloping portion 14 which terminates in a horizontal direction and is provided with a stop 15. If by means of the cylinder 9 the ladder is swung beyond the uppermost position, the rollers 3 will travel over the top of the track 4 and move in a downward'direction along the curve 14, and this causes the entire ladder to be lowered and to take up a horizontal position.

lclaim:

l. A bucket dredger comprising a pontoon, a bucket position.

2. A bucket dredger as claimed in claim 1, said track means being fixedly mounted on said pontoon and occupying the same position both when said ladder is in said upper horizontal position and when said ladder is a ladder and supporting the ladder for bodily vertical 7 lowered dredging position.

3. A bucket dredger as claimed in claim 1, said power means acting between the pontoon and the point of interconnection of the support means to the ladder, said power means being pivotally interconnected both to the pontoon and to the ladder.

4. A bucket dredger as claimed in claim 1, and a 7 discharge chute pivotally interconnected to the upper end of the ladder, and link means acting between the chute and the dredger for maintaining the chute vertical in all vertically adjusted positions of the ladder,

5, A bucket dredger as claimed in claim 4, said support means having a portion that extends beyond its point of interconnection to the ladder, said link means interconnecting said chute and said portion of the support means. 

1. A bucket dredger comprising a pontoon, a bucket ladder, support means pivotally mounted on the Pontoon and pivotally connected to an upper portion of the ladder and supporting the ladder for bodily vertical swinging movement on and relative to the pontoon, upwardly inclined track means carried by the pontoon, roller means carried by the ladder and rolling on the track means to swing the ladder toward a horizontal position when the ladder is swung upwardly on said support means, and power means for swinging the ladder relative to the pontoon, said track means having a summit intermediate the length of said track means so that, upon swinging the ladder upwardly, the roller means first ascend and then descend the track means thereby to position the ladder in an upper horizontal position.
 2. A bucket dredger as claimed in claim 1, said track means being fixedly mounted on said pontoon and occupying the same position both when said ladder is in said upper horizontal position and when said ladder is a lowered dredging position.
 3. A bucket dredger as claimed in claim 1, said power means acting between the pontoon and the point of interconnection of the support means to the ladder, said power means being pivotally interconnected both to the pontoon and to the ladder.
 4. A bucket dredger as claimed in claim 1, and a discharge chute pivotally interconnected to the upper end of the ladder, and link means acting between the chute and the dredger for maintaining the chute vertical in all vertically adjusted positions of the ladder,
 5. A bucket dredger as claimed in claim 4, said support means having a portion that extends beyond its point of interconnection to the ladder, said link means interconnecting said chute and said portion of the support means. 